Combine first 4 ingredients in a food processor. Pulse briefly until combined. Add butter, and pulse to make a coarse meal. Add peanut butter, and pulse briefly to disperse evenly. Be careful not to overmix.
Transfer dough to a large bowl. Add chocolate morsels, if desired. Make a well in center, and add 1/2 cup plus 1 Tbsp. whipping cream and vanilla. Stir with a fork just until dry ingredients are moistened. Knead dough in bowl 2 or 3 times to incorporate dry ingredients in bottom of bowl.
Drop mounds of dough using a 1/3-cup measure onto a baking sheet lined with parchment paper. Smooth tops, and brush scones with remaining cream. Sprinkle with turbinado sugar. Make a deep indentation in center of each scone using thumb or the back of a small spoon; fill each with a scant tablespoon jelly.
Bake at 425° for 18 to 20 minutes or until scones are lightly browned around edges. Cool completely.